Daughter’s house has a rafter adjacent to chimney that is pretty badly rotted. Some other roof structure around chimney also rotted. Problem is poor flashing around chimney. Up there today looking at electrical problems & saw leaks during rain. Will have to remove/replace some sheathing & other structural members. I look at this as a framing carp job for the structural repair & a roofing job for replacing the felt & tarpaper shingles.
Question: can a single rafter be temporarily removed w/o the roof caving in? I suspect it can, since the ridge beam & all the other rafters are good. Actually, I look at it as a sistering problem, since the top 1/5 is all that is bad – sister a replacement section w/ sufficient overlap & cut out the rotted section. House is about 35 yrs old. Rafters appear to be doug fir.
Will be messy – there is the most horrible villain of all growing there – BLACK MOLD. She bought the house July, year & a half ago. Inspectorr’s report noted some “Black Stains” in roof structure, but stated that they were dry & adequate repairs had been made. Moral to this story – don’t have a house in southern MS inspected on a hot, dry day in July!
Nothing about this house surprises me – there is a light switch in the bathroom about a foot outside the tub/shower. All the bathroom vent fans merely vent into the attic space.
Don
The Glass Masterworks
“If it scratches, I etch it!”
Replies
Question: can a single rafter be temporarily removed w/o the roof caving in?
The surest way to tell is this: Remove the rafter. If the roof caves in, then No, it can't. If the roof holds then, Yes, it can. Other than that, everything is just speculation.
And without photos or a diagram, uninformed speculation at that.
=)
"...craftsmanship is first & foremost an expression of the human spirit." - P. Korn
bakersfieldremodel.com
So the question Huck, is would you do it?
I would."...craftsmanship is first & foremost an expression of the human spirit." - P. Korn
bakersfieldremodel.com
so if the rafters are iffy in a couple of places around the chimney then likely the sheeting or roof boards will be too, and since the flashing appears to be the issue it is going to be a better job to pull the shingles, sheet, rafters and flashing from the top instead of the inside. Around the chimney you have to make sure there are no other rafters getting support from the one you need to remove. If the only thing the rafter supports is the shingles and sheeting then yes you can pull it and replace it without allot of elaborate bracing. I have done this for the exact same reasons, and often cut and header off rafters to run ss chimneys. If you are at all nervous or unsure, then start with the sistering approach, or just slide (yeah, likes it ever that easy) the new rafter beside the old then cut it out and wiggle it over. The biggest hassle is usually getting the length into the attic. My pref is to slide them in on flat from the soffit, then twist them upright into place. It's doubtful you'll be able to birdmouth and have rafter and tail in one piece, so scab a 2X lookout on the new rafter and your good to go .. any slack between the rafter and top plate can be taken up with shims .. hopefully your ceiling joists aren't tied into the rafter otherwise you'll have to plan around that too ..
lotsaluck
don-- I haven't collapsed one yet--so you are likely thinking this is gonna be trickier than it really is.
once you remove some roof decking around the chimney you are going to have quite a bit of room to work---almost certainley adequate to sister things in
I don't think I have ever had to go inside the attic to do this on a house-- allthough i have done it from inside on old garages
One thing I WOULD be carefull of---is you likely have plywood decking-and where all the panels line up may limmit your "built in bracing"
we typically have 1x8 decking-maybe decking boards 16' long--so the bad rafter--which isn't carrying any weight by this point--is essentially being supported by 3 or 4 rafters on both sides
best wishes,
stephen
I have decided to do this thing myself. After sleeping w/ it several nights, I came to the same conclusion about the load the bad rafter is carrying. Since I am working at the top end only, any reason why I can't get a 2X8, run it prpendicular to the rafter & tie it to that while I work? It's a 1976 house, so the lumber is pretty dried out. The rot only extends about one rafter bay out from chimney. Went up to inspect after the rains stopped & found the flashing (galvanized) is literally falling out of the mortar. There is a lot of water under the shingles adjacent to & under the flashing. You can see where it is going through. FORTUNATELY - this is at the highest point on the roof, so there's absolutely no doubt where the leaks are. Water doesn't flow up hill! The chimney is solid masonry, about 2 ft wide & 4 ft long, a perfect reaction point to brace the roof against temporarily. There are two hip rafters that have their ends affected & the 2X that they bear on totally rotted out. Looks like that structure bears on the chimney anyway. Have to look more closely at it. Daughter was pretty stressed out when we found it. This house has become a money pit, & this was the latest in a string of major problems to crop up that has to be taken care of before evertything else. We put a tarp over the area, using the chimney to hold it up in center. Nailed it off to areas we know will be replaced & used batttens to do it.
Two questions - Any problems sistering to a hip rafter? All the jacks terminate on it. How on earrth do you do that? If I take about 2 ft off the top end of a 20 ft common rafter, about how much do I have to overlap the sister? I know the fastening schedule for this is critical - should I need an engineer's stamp on that part of the work? Obviously I'm loking to the future when she sells this filled in money pit & potential problems w/ disclosure.
DonDon Reinhard
The Glass Masterworks
"If it scratches, I etch it!"
don,
keeping in mind that I am just a dumb roofer--- it would really be best if some of the framers chime in here however--- generally when I am sistering something I will multiply by at least 3--- if I cut out a 2ft. end- my sister is AT LEAST 6 ft. long I have often driven the nails through both and then clinched the protruding end-- but I have occasionally bolted them as well on your hip-- if you make your sister 6 ft. long- you may have at least 3 pairs of jacks to contend with personally- i wouldn't involve an engineer on this--- but if you are really worried about re-sale-- it would certainley be nice to have an engineers specs assigned to the property so you can show that you did the repair exactly as specified the trick about running a 2x8 perpindicular to the problem rafters--- I have done something like that many times to repair sagging eaves along a gable--- once the roofing is off you can spike a 2x8 or so to about 4-5 adjacent rafters--and then using a few bar clamps pull the entire eave back into plane in your case since you are working with a hip--- you would want to do it from BOTH planes I think to help hold it in place I will be interested in the framers suggestions- maybe I can learn a new trick or a more efficient method as wellStephen
Steve: this is scary - as I do this job mentally in the twilight time between awake asleep, I envsioned just what you have suggested - as my worst case. It seems that, unless everything turns brown & gooey, it should be relatively straightforward w/o serious problems. The only part that I could not truly conceive was how long to make a sister rafter & what kind od fastener schedule to use for the sistering. Not liking to beat laterally on existing structure, I prefer BIG screws, like the ones Piffin pushes. I found them in a lumber yard at home for a job on my own house. I looked in span tables once upon a time shortly after going into the attic the first time & seeing the nightmare of rafters & hips that this roof structure is right on the edge of the envelope for design. Another foot longer & they'd have to be the next size larger. It is also a mix of ages of lumber. It is obvious that the rafters are original from the type wood - fir - patina of the wood & it's growth ring structure. Then there are some support pieces that appear to have been put in later - the wood looks whiter, grain is different & it looks like "White wood," as opposed to fir, like the original. Often, I cannot figure out why the new stuff is in there - UNLESS, as I commented earlier, design at edge of envelope & over the yrs it has started sagging & someone wanted to fix it.
The lumber in this house is a mix. The big pieces are fir. There is a lot of southern yellow pine that today, 30+ yrs later, is as hard as concrete & has a death grip on its nails. It takes a 3 ft wrecking bar to pull them. I've found I'm better off using a recip saw & cutting them. Which brings me to my next question - those "...three pairs of jacks..." you mentioned associated w/ a hip. Sounds like I'll have to get in there & cut them out where I want to run a sister through, then renail them to the new wood. As the guy who really does the work, as opposed to the engineer who designs it, how to do that? I envision taking my 1750 lb Bosch worm drive, lying on my back in the fiberglass & wrestling it into place to at least get a 3 1/2 inch cut that is flat, straight & parallel to the existing hip, followed by my 1750 lb Bosch recip saw to finish the job w/ a wandering, ragged cut to get the last 3 1/2 inches of the end out. Obviously it's going to take saw blades that handle nails.
Before you ROFLYAO at the thought of a glass etcher wrangling lumber & construction work, I need to warn you that in my former life, before I retired, I was an engineer, mucking around w/ construction. So, I know enough to really get into deep trouble. I also learned that the guys doing the job knew a lot more about how to do it than I did, so I asked a lot of questions, most of them starting w/ "Why? or how?". I also learned that there is a big gap between designing something & figuring out how to get from a pile of materials to the final design. Recent examples of that happened in Atlanta, where several people died in a construction accident creating an overhead walkway at the Atlanta Botanical Gardens. Which points out that wet concrete is nowhere near as strong as the fully cured stuff.
Thanks for al the god advice you've given me on this mess. Daughter has a limited budget, so us rank amateurs are going to have to do some of the work.
DonDon Reinhard
The Glass Masterworks
"If it scratches, I etch it!"
don,
one of the framers may be able to give you more specific how to advise however- in the end I don't think this is going to be as bad as you might fear.you might want to put a scab on BOTH sides of the hip rafter--and I think you might simply be able to hold a 2x block along the hip and scribe a pencil line on the existing jack---where this line ends up may be back past the existing nails holding the jack to the hip set your circ saw to the relevant angle--the table should just clear the hip-and make your cut.
depending on which side of the jack you are cutting from-- you might need a circ. saw whose table swing the other way( left blade or right blade.
sawzall the jack stub from the hip. C clamp or bar clamp the sisters in place--drill your bolt holes, bolt it together
re-nail your jacks and the hip sisters in place- and you are just about in the clear.
If possible- have the angled cuts on the end of the hip sisters already made before hand to speed things along a real carpenter would know the correct angles--- me?- I would cheat and use a bevel gauge to set my saw table for the beveled cut.
hopefully I have visualized the situation as it really exists---- but this description probably sounds harder than it really will be. hopefully- you are working with a walkable roof---because if this is 14/12 or something it's gonna be a lot trickier BTW- you MIGHT be able to clamp a2x guide block in place and cut the jack with a hand saw instead of a circ. saw-- but your jacks will then be short the width of your saw blade-which likely won't be all that big of deal in my case-- most of the hip/jack connection I see aren't fitting together like fine cabinetry--being originally cut by hand in the 1920's and baked by roof top temps for 80 plus years.
best wishes,
stephen
Stephen, you are braver than I. I have been following this thread and your suggestions make sense. The only addition I would make is to use a swas all on the Jacks. The reason, probably not enough room for a reg saw. Of course if the wood (ply or real wood) sheathing is coming off, that changes everything.
Either way, this is a pain in the neck>G<
You are aout 2 1/2 feet high in your designation of anatomy. The hemmorhoids are closer to the part you describe for the pain.
DonDon Reinhard
The Glass Masterworks
"If it scratches, I etch it!"
what's a swas?I am assuming he is going to remove some decking--can do the whole thing from above and the table on his saw swings the "right" way for one set of the jacks--but maybe not for the other side?
stephen
Saw all
Unless he has a right and a left saw.
Frammer: Pls see my post today to Stephen Hazlett about this roofing repair.I have decided to do this job myself after reading what I have read in my thread. It is w/i my capability, & financial means. A question:Can a roof bear on a brick chimney? It looks like this one does. The chimney is about 2 X6 ft. The 6 ft sides seem to have what I would call a ridge beam supporting the upper ends of 4 commons & two hips. This beam bears on the chimney side, which is brick. There appear to be absolutely zero nails or other fasteners into the chimney. This beam is a 2X, & would obviously bend under the load of all those rafters & eventually bear on the chimney side. There is a group of these beams on three of the four sides of the chimney, almost like a partial box was built. They are held up by a group of 6 ft long vertical 2X4's that rest on a collar of load bearing walls below the ceiling joists. I'm not sure what these verticals support - half of them are loose.DonDon Reinhard
The Glass Masterworks
"If it scratches, I etch it!"
Can't picture. Do you have a picture?
Frammer - gonna try to do a dwg & attach.DonDon Reinhard
The Glass Masterworks
"If it scratches, I etch it!"
Stephen: you have verbalized what I vizualized quite nicely. Pitch is about 6" rise in 20 ft run. Comfortable to walk on, but if you fell, I think you'd go all the way to the bottom sliding on your butt or whatever is down. A single story ranch w/ a BIG deck in back so a Little Giant ladder easily gets me up there. There is something to be said for bolts - no swinging a hammer to drive spikes into a rock-hard, aged rafter w/ only 14 1/2 inches of swing room.
My Bosch wormdrive has the blade on the left, a natural for a right hander - you can see the blade easily. But being HEAVY, a pain in the hemorhoids to work w/ overhead in cramped conditions.
What you have told me so far has really helped me. I can now vizualize what has to be done, & as I do it in my mind I start seeing challenges to be overcome. You have made simpler a bunch of stuff I either had no concept of as to difficulty or had thought them more difficult than reality.
I'll be doing this job the first week in March, so I have plenty of time to work it through.
Thanks
DonDon Reinhard
The Glass Masterworks
"If it scratches, I etch it!"
Stephen: I just returned from MS, where I was doing a bathroom renovation for daughter when I discovered the really bad roof problem. I did a search on roof repair & discovered that I have been trading e-mails w/ a world-famous author & expert on roofing. Found the FHB article you wrote. What I have to do is very similar to the photos in the article you did. While there, I took some photos of the bad stuff so I could plan the attack on it before returning the first week in Mar to tackle the job. We (daughter & I) successfully wrapped the chimney in a big tarp that survived a several day rain w/o further leakage. I found one board, a 2X, that was completely rotted away, leaving the rafters that bore on it floating in space, apparently held up by the sheathing, like you suggested. I also found a bit more of how the whole mess was cobbled together & what the roof structure was supported on. One whole side of the chimney - about 6 feet, has its rafters unsupported. I recall it is at least 4 commons & two hips. That is going to take interim support while the rot is ripped out. Looks like they built a support structure of the first (& only) floor load bearing walls w/ 2X4 verticals to hold up the ridge beem supporting the upper ends of the commons & hips adjacent to the chimney. There is absolutely no evidence of that beam being attached to the chimney except from the forces of gravity on the roof structure. Couldn't really explore w/o digging through a whole pile of FG insulation. This whole mess is complicated by the existence of (GASP!) BLACK MOLD. That is what destroyed the structure. Fortunately, it is restricted to just a small area surrounding the chimney, except for the one common rafter that sits adjacent to the chimney. It has staining on it the full length of it, in a streak about an inch wide & the plywood has staining about 6 inches out from the rafter. Question - If I have to remove all that sheathing down the potentially bad rafter, should I do so in a manner that keeps me from having a sheathing joint run the full length of a single rafter, thus weakening the roof? Or, should I remove sheathing back to the last joint & replace an entire 4X8 sheet to keep continuity across the rafters?After reading your article, I see how to do the flashing & counter flashing. None of the best practices you mention were followed on this roof. MOF, I can see where the last re-roofing probably caused the problem by violating the integrity of the flashing. Wind blown water was all over underneath the shingles near the chimney, & they were all very loose & floppy.We are fortunate that this is a single family house, hundreds of feet from its neighbor, w/ a driveway that comes right up to the roof edge where we can get rid of our trash directly into a dumpster w/o dumping it over the edge on the lawn & shrubbery.In short, your article gave me a lot of help.Thanks.DonDon Reinhard
The Glass Masterworks
"If it scratches, I etch it!"
don,
I definitely wouldn't want to patch in decking with a continuos seam running all along a single rafter--say an 18 ft. rafter-- I would certainley want things offset.
On the other hand--- if your chimney is right there in the mess I could see how you might end up with 2 panels lined up-- or more likely the top panel isn't a full sheet-and you end up with 1-1/2 sheets lined up with a chimney in the middle of the mess----------
that wouldn't concern me too much--especially with the hip right there. keep in mind- I usually start this sort of boogering after all the roofing is torn off-- the roof load is much lighter.
I am hoping we are talking about actual rafters here By all means keep in mind that at this point the sheathing is mostly holding things up--and that stagger is pretty important to bracing it--so I would try to maintain that stagger/offsetStephen
Stephen: You answered as I suspected about a seam running the entire length of a rafter. This rafter is about 25 ft long! Rise is almost exactly 6 ft from sill plate to ridge. I can stand under ridge beam w/ some clearance, & I'm 5'8". I'll try to make a dwg of this mess & post it IF I can figure out how. This tells me I'm gonna take off a bunch of shingles to expose healthy sheathing to get offsets. So be it. That's why I'll have my 6 foot plus grandson helping me! Looks like he's gonna become fairly proficient at removing shingles!I'm fortunate - the chimney is at the peak of the roof & three hips come together at the chimney. It isn't symmetrically located, however.I'm hoping that when I expose the long rafter that is affected that I won't have to replace anything but the top 3 ft or so w/ a sister. At least if I have to replace the entire rafter, I'll have a clear hole to insert it through - I'll have all the sheathing off it.Since this thing is in MS & you're in OH, I don't feel as guilty picking your brain. I really appreciate your help.I never really appreciated the weight of a roof till I helped my #1 Son do some repairs on the roof structure on his house in Champaign, IL. Someone had put a second roof over the original & caused a couple of the extremely long rafters to sag a bit. It didn't help that there was about 2 ft of snow piled & drifted on it, also. We went in & put a very stiff doubled 2X12 beam in supported on the load bearing walls then jacked up the rafters to get rid of the sag. I am not a fan of putting one roof over another.Don Reinhard
The Glass Masterworks
"If it scratches, I etch it!"
I look at this as a framing carp job for the structural repair & a roofing job for replacing the felt & tarpaper shingles.
For a small job like that, you'd be better off finding someone who can do the whole job.
All the bathroom vent fans merely vent into the attic space.
That's almost certainly the cause of the mold. Venting the fans to the outside - through a gable wall, not the soffit or roof - is as high a priority as the rafter repair.
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